Lung Function Tests Flashcards
What is spirometry?
Test used to asses lung function
What is tidal volume?
Normal volume moved by a normal breath
What is the inspiratory reserve volume?
Air that can still be breathed after normal breath
What is the expiratory reserve volume?
The extra air that can be exhaled after a normal breath
What is the residual volume?
Air that always remains in lungs
Why is there a residual volume?
Prevent alveolar collapse
What is inspiratory capacity?
Tidal volume + Inspiratory reserve volume
What is functional residual capacity?
Expiratory reserve volume + residual volume
What is vital capacity?
The maximum amount of air moved by lungs
What is the total lung capacity?
Vital capacity + residual volume
What can be calculated from spirometry?
FEV1
FVC
FEV1/FVC
What is FEV1?
Forced expiratory volume
Forced expiration in 1st second
What is FVC?
Forced vital capacity
Total volume that can be forcibly exhaled in one breath
What is FEV1/FVC?
Ratio
Compared to normal for height, age, sex
What is normal FEV1?
> 80%
What is normal FVC?
> 80%
What is normal FEV1/FVC?
> 0.7
What patient details do you need when taking spirometry>
Name Age Height Ethnicity Gender
What is the obstructive pattern on spirometry?
Reduced FEV1
Reduced FVC to a lesser extent
Reduced FEV1/FVC
What causes an obstructive pattern?
COPD
Asthma
Emphysema
How is COPD graded?
FEV1
Mild (stage 1) >80%
Moderate (stage 2) 50-79%
Severe (stage 3) 30-49%
Very severe (stage 4) <30%
How do you test reversibility?
Preparation
- no SABA for 6 hours
- no LABA for 12 hours
400mg then repeat after 15 mins
What is the restrictive pattern on spirometry?
Reduced FEV1
Reduced FVC
Normal FEV1/FVC
What causes a restrictive pattern?
Fibrosis
Pulmonary oedema
Skeletal abnormalities
Neuromuscular diseases
